DE2736059A1 - PROCESS FOR THE PREPARATION OF 2,6-DI-TERT.-BUTYLPHENOL - Google Patents

Description

SHIP ν. FONER STREHL SCHDLL .-- h ..'- PF E; "J ^- 3ltsKi: IAUS RNCX description

The present invention relates to the petrochemical and chemical industries, in particular to Process for the production of 2,6-di-tert-butylphenol, which is polymeric in the production of stabilizers Materials is used.

Ee is a process for the production of 2,6-di-tert-butylphenol by alkylating phenol with pure isobutylene in the presence of aluminum dissolved in phenol as Catalyst known (PT-PS 1 137 444, Stroh B., Seydel E., Hohn W., Angew. Chem., 69t 6991 »1957) ·

In this case, ortho-tert-butylphenol is obtained and 65 to 70 mole percent 2,6-di-tert-butylphenol. A disadvantage of the process is the high cost of the pure used Isobutylene, which is separated from hydrocarbons containing isobutylene using special methods.

It is alkylation of the phenol with n-butenes at a temperature of 140 to 24O ⁰ C in the presence of dissolved aluminum in phenol as a catalyst known. At a temperature of 15O ⁰ C, the yield of 2-sec-butylphenol 27.5 mole percent (DT-PS 2,333,745).

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A process for the preparation of 2,6-di-tert-butylphenol in admixture with 2-tert-butylphenol is also known. The alkylation of the phenol is reacted with a Gcaisch about $ 0 Iviolprozent isobutylene containing XGomeior butenes in the presence of dissolved aluminum in phenol as a catalyst in eir.er temperature of 70 to ⁰ C, vorzugoivcdüe 90 to 130 ⁰ C.

The disadvantage of this process is the formation in the Process of 2-sec-butylphenol as a by-product, its Concentration depends on the isobutylene content of the mixture of isomeric butenes.

Table 1 gives information which shows the selectivity of the alkylation process as a function of the initial and final isobutylene content of the mixture of isomeric butenes.

Table 1.

Versu Temperature Isobutyl egg
• ^ icon cntra
»Mix the
% ; ~ Final concentration - 2 sec.
-Butyl-
phenol ches ⁰ C Starting
concentra
tion End con
center
tion 2,6-di-tert.
-Butylph-
nol 0.7
3.2 1
2 110
110 45.4
45.4 20.4
4.1 65.5
66.2

The table shows the following. The higher the conversion of isobutylene, the more by-product, 2-sec.-butylpb.enol, is formed. The presence of the

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named by-product leads to the fact that the mixture in dom the isobutylene contained in the isomeric butenes is partly used, which is economically unacceptable. It it is not possible to completely separate off the isobutylene with a high selectivity of the process. Those after the alkylation process remaining n-buteno, the 20.4 molprosont Containing isobutylene are not widely used.

The purpose of the present invention is to provide the aforementioned Avoid disadvantages.

The invention is based on the object in the process for the production of 2,6-di-tert-butylphenols to choose such conditions for carrying out the process, which make it possible to achieve a high degree of conversion of icobutylene with a simultaneous reduction in the yield of by-products.

This object is achieved in that in the process for the preparation of 2,6-di-tert-butylphenol by alkylating the phenol with a mixture of the isomeric butenes in the presence of aluminum dissolved in the phenol as a catalyst with heating, according to the invention the alkylation of the performs phenol in the presence of mono-tert.-butylphenol with stepwise lowering of the temperature of the process of 120 ⁰ C to 50 ° C and reducing the concentration of isobutylene in the mixture of isomeric butenes from 80 mole percent to 1.5 mole percent ·

Is advantageously carried out the alkylation of phenol in the presence of 20 to 50 mole percent mono-tert-butylphenol by ·

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The method according to the invention is carried out as follows.

In the alkylation of the phenol with the mixture of isomeric butenes depends on the rate of formation of the 2-eec.-butylphenol on the degree of alkylation of the phenol with the isobutylene. With an increase in the degree of alkylation of phenol, the rate of alkylation both with isobutylene is reduced at the same time as well as with n-butenes. However, the rate of alkylation of phenol with n-butenes is reduced significantly faster, as can be seen from Table 2.

Table 2.

Concentration of the phenol in a mixture with mono-tert.- -buty! phenol, mole »%

relative decrease in the rate of alkylation of the phenol

with isobuty- with n-butylene len

100 90 80 70 60 50

1.0

0.93

0.86

0.78

0.70

0.63

1.0

0.74 0.43 0.30 0.21 0.12

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As can be seen from Table 2, to increase the degree of alkylation of the phenol mono-tert.- -butylphenol add in an amount that the concentration of the starting phenol does not exceed 80 mole percent. The alkylation of the phenol is preferably carried out in the presence from 20 to 50 mole percent mono-tert-butylphenol through.

The temperature has an effect on the relative rate of alkylation of the phenol with isobutylene and n-butenes the alkylation reaction has a strong influence. With increasing reaction temperature, the ratio of Constants of the rate of alkylation of phenol with n-butenes and isobutylene increase and it grows accordingly the 2-sec-butylphenol content of the reaction products. The influence of temperature on the ratio of the constants the rate of alkylation of phenol with n-butenes and isobutylene is shown in Table 5 *

Table 3.

m _emr4A _ _e4 . "" Ratio of the constants of the

temperature, speed of alkylation of the

C nols with n-butenes and isobutylene

90 1170

110 580

130 270

The greatest amount of 2-sec-buty! Phenol is formed at low concentrations (less than 5 mole percent) of the isobuxylene in the mixture of isomeric butenes and in

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In this case, the temperature of the alkylation reaction should be reduced to a minimum. So that the reaction time is not too long, the temperature must be increased at a higher concentration of isobutylene in the mixture of isomeric butenes. In view of the fact that the maximum yield of 2,6-di ~ te.rt.-butylphenol is observed at a temperature not exceeding 120 ⁰ C, it is undesirable to begin the alkylation process at höhexer temperature.

To prepare 2,6-di-tert-butylphenol by the process according to the invention, the Catalyst of the alkylation process, aluminum dissolved in phenol, by any known method.

Mono-tert-butylphenol is added to the molten starting phenol, which contains the catalyst mentioned, and this mixture is fed to the upper part of the reactor 2 through the drilling line. The concentration of the phenol in the mixture must not exceed 80 mol percent. The reactor is divided into 5 zones in the event that the starting phenol enters the reactor at a concentration greater than 80 mol percent. The mono-tert-butylphenol is passed according to its formation in the process of alkylation from zone 5 or zone 4 with the pump 5 through the pipe 6 for mixing with the starting phenol in such a way that the phenol concentration at the inlet to the Reactor does not exceed 80 mole percent. The mixture of isomeric butenes is fed in through pipe 7 of reactor 2. With the decrease in

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Concentration of isobutylene of from 80 mole percent to 1.5 mole percent in the mixture of isomeric butenes decreases the temperature in the reactor of 12O ⁰ C in the lower part of the reactor at 50 ⁰ C in the upper part of the reactor. A mixture of n-butenes which contains 2 to 5 percent by weight of isobutylene is removed from the top of the reactor through pipeline 8. A mixture of tert-butylphenols is passed out of the lower part of the reactor through pipeline 9, from which 2,6-di-tert-butylphenol is separated off by rectification after the catalyst has been destroyed with water.

By changing the conditions for carrying out the process, a high degree of isobutylene conversion is achieved compared to the known process for the production of 2,6-di-tert-butylphenol without lowering the quality of the End product reached. In addition, the amount of by-products formed is 2 to 5 times less than after the known process for the preparation of 2,6-di-tert-butylphenol. The n-butenes after the alkylation of the phenol. contain less than 5 mole percent isobutylene Widely used in industry for the manufacture of divinyl, methyl ethyl ketone and other products.

For a better understanding of the present invention, the following specific examples are given for its implementation.

Example 1 «

0.7 g of metallic aluminum is dissolved in 40 g of phenol

at a temperature of 160 ° C, the solution cools to a

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Temperature of 100 ^° C. and gives 62 β 2-tert-butylphenol fraction of the following composition: 2-tert-butylphenol 96.7 mol percent; Phenol 2.4 mole percent; 2,6-di-tert-butylphenol 0.9 mole percent. The mixture obtained is cooled to a temperature of 50 ° C. and fed to the upper part of a counter-flow reactor. 155 S of a mixture of the isomeric butenes containing 78 mol percent isobutylene are fed to the lower part of the reactor. As the concentration of isobutylene in the mixture of isomeric butenes decreases, the temperature in the reactor falls from 120 ^° C. in the lower part of the reactor to 50 ^° C. in the upper part of the reactor. A mixture of the isomeric butenes which contains 2 mol percent isobutylene emerges from the top of the reactor. A mixture of the alkylphenols with the following composition emerges from the lower part of the reactor in an amount of 225 g : tert-butyl ether 0.5 mol percent; Phenol 0.4 mole percent; 2-tert-butylphenol 23 »1 mol percent; 2 sec. -Butylphenol 0.2 mole percent; 4-tert-butylphenol- 0.2 mole percent; 2,6-di-tert-butylphenol 61.5 mole percent; 2,4-di-tert-butylphenol 6.0 mole percent; 2,4 £ -tri-tert-butylphenol 8.5 mole percent. After the catalyst has been destroyed with water, 145 g of 2,6-di-tert-butylphenol are separated off from the mixture of alkylphenols by rectification. The yield is 61 mole percent.

When a higher degree of separation of the isobutylene is achieved up to 2% , the concentration of the 2-sec is. -Butylphenol 0.5 mol percent, based on the 2t6-di-tert-butylphenol. _ÄÄ

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Example 2 .

In 64.3 g of phenol 1.1 g aluminum dissolves at a temperature of 160 ⁰ C, the solution is cooled to a temperature of 10O ⁰ C and gives 26.7 g of 2-tert-butylphenol to. The mixture is cooled to a temperature of 50 ° C. and fed to the top of a countercurrent reactor. 250 g of a mixture of isomeric butenes containing 50 percent by weight of isobutylene are fed to the lower part of the reactor. With decreasing concentration of isobutylene in the mixture of isomeric butenes, the temperature drops in the reactor of 120 ⁰ C in the lower part of the reactor to 5O ° C in the upper part of the reactor. A mixture of the isomeric butenes which contains 1.7 mol percent isobutylene emerges from the top of the reactor. 234 g of a mixture of alkylphenols with the following composition emerge from the lower part of the reactor: tert-butyl ether 0.4 mol percent; Phenol 0.5 percent} 2-tert-butylpb.enol 21.1 percent; 4-tert-butylphenol 0.2 mole percent; 2-sec-butylphenol 0.2 mole percent; 2,6-di-tert-butylphenol 65.0 mole percent; 2,4-di-tert-butylphenol, 5.0 mole percent; 2,4,6-tri-tert-butylphenol 7.6 mol percent · After the catalyst has been destroyed with water, 159 g of 2,6-di-tert-butylphenol are separated from the mixture of alkylphenols by rectification. The yield is 65 mole percent

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Example 3 .

63 g of phenol are heated to a temperature of ICO ⁰ C, 5.6 ml of triisobutylaluminum are poured in under a stream of dry nitrogen, 43.5 g of 2-tert-butylphenol are added. The mixture is cooled to a temperature of 50 ° C and feeds to the top of a countercurrent reactor. 255 β of a mixture of the isomeric butenes which contains 45 mol percent isobutylene is fed to the lower part of the reactor. The alkylation reaction is carried out under the conditions of Example 1.

A mixture of the isomeric butenes, which contains 1.5 mol percent isobutylene, emerges from the top of the reactor. 220 g of a mixture of alkylphenols with the following composition emerge from the lower part of the reactor: tert-butyl ether 0.2 mol percent; Phenol 0.8 mole percent; 2-tert-butylphenol 23 »6 mole percent; 4-tert-butylphenol 0.4 mole percent; 2-sec-butylphenol 0.2 mole percent; 2,6-di-tert-butylphenol 61.8 mole percent; 2,4-di-tert-butylphenol 5.2 mole percent; 2,4,6-tri-tert-butylphenol 7.8 mol percent · After the catalyst has been destroyed with water, 142 g are separated from the mixture of alkylphenols by eectification 2,6-di-tert-butylphenol. The yield is 65 mole percent.

Example 4 .

55 β 4-tert-butylphenol are added to 53 g of phenol. The mixture is heated to a temperature of 100 ⁰ C, poured g of triisobutylaluminum under a dry nitrogen stream to 5.0, then cooled to a temperature of 50 ° C and

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feeds it to the top of a countercurrent reactor. To the 286 g of a mixture of the isomeric butenes are fed to the lower part of the reactor, which gives 4-5 percent by weight isobutylene contains. The alkylation reaction is carried out under the loading. conditions of example 1.

A mixture of the isomeric butenes, which contains 2.6 mol percent isobutylene, emerges from the top of the reactor. 235 S of a mixture emerge from the lower part of the actuator of the alkylphenols with the following composition: tert-butyl ether 0.6 mol percent; Phenol 0.4 mole percent; 2-tert-butylphenol 20.5 mole percent; 2-sec-butylphenol 0.2 mole percent; 4- »tert-butylphenol 19.2 mol percent, 2,6-di-tert-butylphenol 28.0 mol percent; 2,4-di-tert-butylphenol 15.1 mole percent; 2,6-tri-tert-butylphenol 16.0 mole percent. To the destruction of the catalyst with water is separated from the mixture of alkylphenols by Bectification 153 β 2,6-di-tert-butylphenol. The yield is 65 mole percent.

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Le e rs e ι te

Claims (2)

SHIP ν. FÜNER STRHHL SCHUnEL-KOPF EBBINGHAUS FINCK MARIAHILFPLATZ 2 * 3, MÖNCHEN ΘΟ POSTAL ADDRESS) POST BOX Θ5 O1 6O, D-8OOO MÖNCHEN Θ5 Sterlitamakskij opytno-promyslennyj neftechimitscheskij zavod Novokuibyschevskij filial giprokautschuka KARL LUOWIQ SHIP DIPL. CHEM. DR. ALEXANDER V. FÜNER DIPL. IN O. PETER STREHL DIPL. CHEM. DR. URSULA SCHÜBEL-HOPF DIPL. INQ. DIETER EBBINQHAUS DR. INO. DIETER FINCK TELEPHONE (ΟβΟ) 48 SO 54 TELEX β-23 666 AURO D. TELEQRAMS auromarcpat Munich DA-18127 August 10, 1977 PROCESS FOR MANUFACTURING 2,6-DI-TERT.-BUTYL- PHENOL Claims \ J / Process for the preparation of 2 _f 6-di-tert-butylphenol by alkylating phenol with a mixture of the isomeric butenes in the presence of aluminum dissolved in the phenol as a catalyst with heating and subsequent separation of the end product, characterized in that the Carries out alkylation of the phenol in the presence of mono-, tert-butylphenol with gradual lowering of the process temperature from 12O ⁰ C to 50 ⁰ C and with reduction of the concentration of isobutylene in the mixture of isomeric butenes from 80 mol percent to 1.5 mol percent. 2. The method according to claim 1, characterized 809807/0792 ORIGINAL INSPECTED draws that the alkylation of the phenol is carried out in the presence of 20 to 50 mol percent mono-tert-butylphenol. 809007/0792